EP0229851A1 - Verfahren zur bearbeitung eines gebietes - Google Patents

Verfahren zur bearbeitung eines gebietes Download PDF

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Publication number
EP0229851A1
EP0229851A1 EP86904383A EP86904383A EP0229851A1 EP 0229851 A1 EP0229851 A1 EP 0229851A1 EP 86904383 A EP86904383 A EP 86904383A EP 86904383 A EP86904383 A EP 86904383A EP 0229851 A1 EP0229851 A1 EP 0229851A1
Authority
EP
European Patent Office
Prior art keywords
convex polygon
centroid
convex
point
area
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP86904383A
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English (en)
French (fr)
Other versions
EP0229851B1 (de
EP0229851A4 (de
Inventor
Kunio Tanaka
Yasushi Onishi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fanuc Corp
Original Assignee
Fanuc Corp
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Filing date
Publication date
Application filed by Fanuc Corp filed Critical Fanuc Corp
Publication of EP0229851A1 publication Critical patent/EP0229851A1/de
Publication of EP0229851A4 publication Critical patent/EP0229851A4/de
Application granted granted Critical
Publication of EP0229851B1 publication Critical patent/EP0229851B1/de
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/402—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/41—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by interpolation, e.g. the computation of intermediate points between programmed end points to define the path to be followed and the rate of travel along that path
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00—Program-control systems
    • G05B2219/30—Nc systems
    • G05B2219/49—Nc machine tool, till multiple
    • G05B2219/49381—Raster, line servo, area machining, cutting, facing

Definitions

  • This invention relates to an area cutting method and, more particularly, to an area cutting method through which the interior of an area bounded by a closed curve can be cut efficiently.
  • Forms of numerically controlled machining include cutting in which the interior of an area bounded by a closed curve is hollowed out down to a predetermined depth, and die milling in which the interior of an area is die milled. In such machining, as shown in Fig.
  • an area cutting method is conventionally carried out by performing cutting along an (i-l)th cutting path PTi-1 in one direction (the direction of the solid line arrow), raising the tool a predetermined amount at the completion of cutting, then positioning the tool directly above a cutting starting point Ps on the next, or i-th, cutting path PTi, thereafter lowering the tool to the cutting starting point Ps, moving the tool along the i-th cutting path PTi in the direction of the solid line arrow, and subsequently repeating the above unidirectional cutting.
  • FIG. 8(B) Another area cutting method shown in Fig. 8(B) includes, following completion of cutting along the cutting path PTi-1 of the (i-l)th cutting path, moving the tool from a cutting end point Pe to the cutting starting point Ps on the next, or i-th, cutting path, and thereafter performing cutting along the i-th cutting path PTi.
  • cutting is performed back and forth in the direction of the arrows.
  • Still another area cutting method shown in Fig. 8(C) includes obtaining offset paths OFCl, OFC2,... OFCn offset by predetermined amounts with respect to a curve OLC of an external shape, and moving the tool successively along the offset paths.
  • the tool must be positioned at the cutting starting point Ps on the i-th cutting path PTi after the completion of cutting along the (i-l)th cutting path PTi-1.
  • This method is disadvantageous in that it results in a long tool traveling distance.
  • the cutting processes referred to here indicate up cutting and down cutting processes.
  • Figs. 9(A), (B) show examples of the down cutting process
  • Figs. 9(C), (D) depict examples of the up cutting process.
  • a cutting method capable of cutting the workpiece efficiently is selected from the up cutting and down cutting processes.
  • the up cutting process [e.g. Fig. 9(A)] and the down cutting process [e.g. Fig. 9(C)l are always mixed, so that cutting cannot be performed efficiently.
  • portions are left uncut at, e.g., the central portion of the area, depending upon the contour of the external shape curve.
  • This method is disadvantageous in that dealing with these uncut portions is a complicated task.
  • Figs. 10(A), (B) are views for describing this area cutting method.
  • the area cutting method is composed of the following steps:
  • area cutting can be carried out while moving the tool continuously. This is advantageous in that it eliminates wasted tool movement and shortens cutting time in comparison with the prior-art method. It also does not leave any uncut portions at, e.g., the central part of the area.
  • the cut-in pitch of a smaller convex polygon is considerably shorter than that of a larger convex polygon [(see the cut-in pitches t 1 1 t 2 of convex polygons PG1, PG2 in Fig. 10(B)].
  • an object of the present invention is to provide an area cutting method in which the number of cutting paths of each convex polygonal portion is varied in dependence upon the size of the convex polgyon so that any convex polygonal portion can be cut at a cut-in pitch close to that of an allowable cut-in pitch.
  • Another object of the present invention is to provide an area cutting method in which a small convex polygonal portion can be cut efficiently with a small amount of tool movement.
  • the present invention relates to an area cutting method in which a tool is moved along a plurality of paths successively offset in an inward direction from a closed curve specifying an area, or in other words, in which the tool is moved in a spiderweb-like pattern, to cut the interior of the area. More particularly, the invention relates to an area cutting method in which, when an area is partitioned into a plurality of convex polygons, the number of cutting paths in each convex polygonal portion is decided in dependence upon the size of the convex polygon and the cut-in pitch (path interval) of each convex polygonal portion is made substantially the allowable cut-in pitch.
  • the cut-in pitch of each convex polygonal portion is made substantially the allowable cut-in pitch, thereby improving cutting efficiency.
  • Fig. 1 is a view for describing the general features of an area cutting method according to the present invention.
  • the area cutting method of the invention is basically composed of the following eight steps:
  • Fig. 2 is a block diagram of an NC system for practicing the area cutting method of the present invention
  • Fig. 3 is a flowchart of processing. The area cutting method of the present invention will now be described in conjunction with Figs. 1 through 3.
  • Area cutting data necessary for area cutting are recorded at appropriate locations on an NC tape or memory (assumed to be an NC tape hereafter) 101 shown in Fig. 2.
  • the processor 103 finds incremental values Xi, Yi, Zi along the respective axes as well as amounts of movement ⁇ X, ⁇ Y, ⁇ Z along the respective axes per unit time ⁇ T based on feed rate F. These are inputted to a pulse distributor 106.
  • the pulse distributor 106 On the basis of the input data, the pulse distributor 106 performs a simultaneous three-axis pulse distribution calculation to generate distributed pulses Xp, Yp, Zp. These are delivered to servo circuits 110X, 110Y, 110Z for the respective axes to transport the tool along the cutting path.
  • the processor 103 in accordance with the following formulae, updates the present position X a , Y a Z every ⁇ T sec, X , Y a , Z having been stored in a RAM 111:
  • the processor 103 updates remaining traveling distances X r , Y r , Z (the initial values of which are the incremental values X., Y i , Z i , respectively) every ⁇ T sec, X r , Y r , Z r having been stored in the RAM 111:
  • the processor 103 treats this as indicating that the movable element has arrived at a target position and causes the NC data reader 104 to read the next item of NC data.
  • the processor 103 causes the NC data reader 104 to read the area cutting data and store the data in the RAM 111 until the code indicating the end of the area cutting data is read out.
  • the processor 103 checks the NC data to determine whether it is a code indicative of the end of the area cutting data.
  • the tool radius ra is obtained by reading a radius value corresponding to a commanded tool number from an offset memory 112, which stores the correspondence between tool numbers and tool radii.
  • the offset curve OFC is found through the following processing. Specifically, as shown in Fig. 4, let two straight lines specifying the curve OLC of the external shape be Sl and S2. Straight lines Sl l , S2' offset from the straight lines Sl, S2, respectively, by the distance D are found. The intersection P2 of the straight lines Sl l , S2' is then found. The intersection P2 is one point specifying the offset curve OFC. Accordingly, if points of intersection are found in a similar manner and stored in the RAM 111, the offset curve OFC will be obtained.
  • the processor 103 now linearly approximates a circular arc portion of the offset curve OFC if the curve has a circular arc portion.
  • Fig. 5 is a view for describing the linear approximation processing.
  • the maximum distance d between the circular arc Al and the straight line (chord) LN is given by where the radius of the arc is r and the central angle of the chord LN is ⁇ . Accordingly, the central angle 9 for which d ⁇ P holds, namely the central angle 0 that satisfies the relation is found, the central angle ⁇ of the circular arc Al is partitioned at the angle ⁇ and the coordinate values of each partitioning point R i are stored in the RAM 111. This ends the processing for linear approximation of the circular arc portion.
  • the processor 103 performs convex polygon creation processing for dividing, into plural convex polygons, the area bounded by an offset curve (OFC in the embodiment of Fig. 1), obtained by the linear approximation.
  • OFC offset curve
  • two convex polygons PGl, PG2 are created by this convex polygon creation processing in the case of Fig. 1.
  • convex polygon creation processing see the specification of U.S. Serial No. 776,205.
  • the coordinate values of the centroid of a convex polygon are calculated through processing which will now be described.
  • a convex polygon P G is broken down into a plurality of triangles TR1 through TR3 and the centroids Wll through Wl3 and areas SQ1 through SQ3 of the respective triangles are calculated.
  • a point W21 that divides a line segment W12Wll connecting the centroids Wll, W12 into the ratio SQ1:SQ2 (area ratio) is found.
  • the point W21 is the centroid of a quadrilateral P1P2P3P4.
  • a point Wl is found that divides a line segment W13W21 into the area ratio (SQI+SQ2):SQ3.
  • the point Wl is the centroid of the convex polygon PG.
  • the processor 103 finds the line segment having the longest length among the line segments (Sll - S16; S21 - S24) connecting the respective centroids and apices.
  • line segment S16 is the longest for convex polygon PG1
  • line segment S23 is the longest for convex polygon PG2.
  • the processor finds a number of partitions Nl for which a length of a partitioned line segment obtained by equally partitioning the longest line segment S16 will have a value closest to the cut-in pitch P without exceeding the cut-in pitch P. Similarly, the processor finds a number of partitions N2 with regard to the longest line segment S23. Thus, the processor obtains a number of partitions Ni for each longest line.
  • the processor 103 obtains the largest number of partitions M and the largest convex polygon.
  • M 10 and the largest convex polygon is PG1.
  • the processor obtains partitioning points qll - q13, q21 - q23 which respectively divide, into m equal parts, two line segments BL1, BL2 connecting the point K1 with the two end points P14, P15 of boundary line Bl, which is bisected by the mid-point Ml.
  • the processor 103 generates closed paths CPl - CP3 successively connecting corresponding partitioning points of line segments Sij (Sll - S16, S21 - S24) connecting the centroid and apices of each convex polygon, of the two line segments BL1, BL2 connecting the point Ki (Kl) and points P14, P15, and of the median lines Bl, B2.
  • closed path CPl is Q71 ⁇ Q76 ⁇ Q75 ⁇ qll ⁇ m11 ⁇ R14 ⁇ R13 ⁇ R12 ⁇ Rll ⁇ m21 ⁇ q21 ⁇ Q74 ⁇ Q73 ⁇ Q72 ⁇ Q71
  • closed path CP2 is Q81 ⁇ Q86 ⁇ Q85 ⁇ q12 ⁇ m12 ⁇ R24 ⁇ R23 ⁇ R22 ⁇ R21 ⁇ m22 ⁇ q22 ⁇ Q84 ⁇ Q83 ⁇ Q82 ⁇ Q81.
  • the closed path CP3 is similarly generated.
  • CPo is Q61 ⁇ Q66 ⁇ Q65 ⁇ Kl ⁇ Ml ⁇ W2 ⁇ Ml ⁇ K1 ⁇ Q64 ⁇ Q63 ⁇ Q62 ⁇ Q61.
  • step (18) would entail generating a plurality of closed paths connecting corresponding partitioning points of the plural line segments, which connect the centroid and apices of each convex polygon, and of the median lines.
  • the processor 103 obtains numerical data (incremental values between an initial position and the starting point Wl) for making the tool approach the starting point Wl from the initial position, and thereafter executes ordinary path control using the incremental values.
  • the processor 103 moves the tool to the point Qll in the cutting mode, then moves the tool along the first closed path LP1 in a cutting feed mode and thereafter moves the tool successively along LP2, LP3, .. LP5, CPo, CPl, CP2, .. CP3 in a similar manner to perform cutting.
  • the tool movement sequence is LPl ⁇ LP2 ... LP5 ⁇ CPo ⁇ CP1 ⁇ CP2 ⁇ CP3 when performing cutting, it is permissible for the sequence to be reversed.
  • the invention has been described on the premise that a single convex polygon is adjacent to the largest convex polygon, the invention is not limited thereby but can also be applied to a case where other convex polygons PG21, PG31 are connected to the convex polygon PG4, as shown in Fig. 7(B).
  • the number of partitions Ni of the convex polygon PG4 would be decided upon taking the other convex polygons PG31, PG21 into consideration. More specifically, if the convex polygon PG4 is the largest or second largest, the number of partitions Ni of this convex polygon is decided irrespective of the convex polygons PG21, PG31.
  • the number of partitions Ni of the convex polygon PG4 is the number of partitions of the second largest convex polygon PG31.
  • NC tape NC data
  • NC data NC data
  • the number of cutting paths of convex polygonal portions is changed depending upon the size of the convex polygonal portions in a method of cutting an area along paths defining a spider web-like pattern.
  • cutting is performed at a cut-in pitch close to an allowable cut-in pitch regardless of the convex polygonal portion. This enables small convex polygonal portions to be cut with a small amount of tool movement, thus making it possible to raise area cutting efficiency in comparison with the prior-art method.

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  • Engineering & Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Computing Systems (AREA)
  • Theoretical Computer Science (AREA)
  • Numerical Control (AREA)
  • Milling Processes (AREA)
EP86904383A 1985-07-17 1986-07-17 Verfahren zur bearbeitung eines gebietes Expired - Lifetime EP0229851B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP157926/85 1985-07-17
JP60157926A JPS6219907A (ja) 1985-07-17 1985-07-17 領域加工方法

Publications (3)

Publication Number Publication Date
EP0229851A1 true EP0229851A1 (de) 1987-07-29
EP0229851A4 EP0229851A4 (de) 1989-12-12
EP0229851B1 EP0229851B1 (de) 1993-09-15

Family

ID=15660487

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86904383A Expired - Lifetime EP0229851B1 (de) 1985-07-17 1986-07-17 Verfahren zur bearbeitung eines gebietes

Country Status (6)

Country Link
US (1) US4823273A (de)
EP (1) EP0229851B1 (de)
JP (1) JPS6219907A (de)
KR (1) KR900007160B1 (de)
DE (1) DE3689039T2 (de)
WO (1) WO1987000648A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2282899A (en) * 1993-10-15 1995-04-19 British Aerospace Numerically-controlled machinery

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2669822B2 (ja) * 1987-05-19 1997-10-29 三洋電機株式会社 作業車の作業経路決定装置
JPH0827651B2 (ja) * 1987-05-19 1996-03-21 三洋電機株式会社 作業車の作業経路決定装置
JP2629759B2 (ja) * 1987-12-22 1997-07-16 セイコーエプソン株式会社 数値制御加工用データ生成方法
FR2646727B1 (fr) * 1989-05-03 1991-07-26 Num Sa Procede de determination automatique du trajet d'outil dans un usinage plan de poches
GB9914603D0 (en) * 1999-06-22 1999-08-25 Fetherstonhaugh Tristram A method,apparatus and computer program for shaping material
AU2008326228B2 (en) * 2007-11-09 2013-05-02 Bae Systems Plc Improvements relating to methods of fabricating structural elements
KR101850005B1 (ko) 2016-04-05 2018-04-18 자동차부품연구원 캠 샤프트 장치 및 캠 샤프트 장치의 제작 방법
CN117655563B (zh) * 2024-01-31 2024-05-28 成都沃特塞恩电子技术有限公司 激光切割路径规划方法、装置、电子设备及存储介质

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DE3113970A1 (de) * 1981-04-07 1982-11-04 Dr. Johannes Heidenhain Gmbh, 8225 Traunreut Numerische bahnsteuerung fuer eine werkzeugmaschine
JPS57169814A (en) * 1981-04-10 1982-10-19 Fanuc Ltd Forming method of curved surface
JPS5835607A (ja) * 1981-08-27 1983-03-02 Fanuc Ltd 数値制御装置
JPS6090653A (ja) * 1983-10-22 1985-05-21 Fanuc Ltd 領域加工方法
WO1985001908A1 (en) * 1983-10-31 1985-05-09 Fanuc Ltd Machining method for machine tools
JPS60155342A (ja) * 1984-01-10 1985-08-15 Fanuc Ltd 領域加工方法
JPH0663606A (ja) * 1992-08-19 1994-03-08 Kobe Steel Ltd 金属箔の圧延方法
JPH0690653A (ja) * 1992-09-08 1994-04-05 Marutomo:Kk サンドイッチ状干菓子類の生地成形装置

Non-Patent Citations (1)

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Title
See references of WO8700648A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2282899A (en) * 1993-10-15 1995-04-19 British Aerospace Numerically-controlled machinery
GB2282899B (en) * 1993-10-15 1998-04-29 British Aerospace Numerically controlled machinery

Also Published As

Publication number Publication date
WO1987000648A1 (en) 1987-01-29
JPS6219907A (ja) 1987-01-28
DE3689039D1 (de) 1993-10-21
EP0229851B1 (de) 1993-09-15
US4823273A (en) 1989-04-18
KR900007160B1 (ko) 1990-09-29
DE3689039T2 (de) 1994-01-27
EP0229851A4 (de) 1989-12-12
KR880700338A (ko) 1988-02-22

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